Building a crystal radio isn’t exactly rocket science. Some people who build them go for pushing them technically as far as they can go. Others, like [Billy Cheung], go for style points. The modular radio and phone speaker looks like it came out of the movie Brazil. The metallic gramophone-like speaker horn adds to the appeal and mechanically amplifies the sound, too.
The video (see below) isn’t exactly a how-to, but if you watch to the end there is enough information that you could probably reproduce something at least similar. There are actually several horns. One is made from copper, another from paper, and one from a plastic bottle.
There’s also a socket to take different detectors. The radio appears to have a great frequency range, although you’ll have to squint at the video to see the schematic. We are hoping [Billy] will have it posted on his blog, too, eventually. Same goes for the templates for cutting out and assembling the horns. However, if you freeze the video, you can see most, if not all, of the major components.
We’ve seen [Billy] around here before with simple crystal radios. If you want to see just how far you can go with a crystal radio obsession, look no further than this.
The one made from PLATIC BOTTLES is ugy.
The custom hand dials are awesome best bit is at the back
Nice project
If I could hold my hands to my mouth and say “this is not an amplifier” … !
Auxetophone. That is an amplifier! Non electric but still with a source of power, and hence gain. NASA made a subwoofer in the 60’s using that tech that put out about 500 dB! Rattle the $%*T out of what is to be launched to the moon.
A horn is just a transformer, changing impedance only. Transforming the mass of a moving solid mass, to the lightness of air. Kinda like low volts to high voltage, or a lever, or higher gears on a bike.
Not at the Sparrow but the Spot I am talking the chainsaw wielding maker of furniture in the biergarten to make or exploit such horns into the logs he shapes. Eventuality they will end up in the fire.
Look up the history on horn and early loudspeakers bell labs etc.
You just answered a question that I have had for so long!!
That’s very neat
That is a beautiful build.
Was that an iPhone though? Too bad, he will probably get sued by Apple for building an unlicensed accessory or something. He should have gone with something from a less anti-hacker/maker company.